What thickness flange is yours?
I had one cut on our laser, but did it out of 8/10mm(can't remember which), but my old man went to a kit car show a few weeks back and people were selling them out of 6mm? Seems a bit thin to me

Also, what size tube is best used for the primaries?

Thanks
Ben.

 

Anyone?

 

if the primarys are long then 1.5 inch will be fine upto 500bhp , but if you used a larger tube like 1 5/8 with short primarys (like a focus rs manifold) then you would probably gain a few bhp but the torque would rise .
i use on my over gearbox manifolds 1.5 inch primarys , 1.5mm thickness and 10mm thickness stainless steel flanges both header and turbo flange
even the 10mm stainless flanges are bolted down during welding to stop the flange from twisting

hope this helps

 

My twin scroll top mount setup uses a 12.6mm (1/2") mild steel flange and 4mm wall thickness primaries.

Admittedly it will have a harder life than most, hence the 'meatiness' of it all...

 

Now that looks cool

 

I have one of ian Howells manifolds

Great bit of kit

 

Thanks for the replies guys, I should of said what spec I'll be running!
I'm building a KA with a 2.0 Zetec, very lightweight and basic breathing mods and cams for the time being, as we have a pipe bender and laser I figured we could make our own exhaust including the manifold, so at the very most, 150bhp for the time being which should be more than enough while I source some parts for a turbo conversion.

Ben.

 

what kind of pipe bender?
if it's not a mandrel one don't bother IMO.

 

Yes it's a mandrel mate.